Summer 2008 Newsletter

Myth Busters: Watered-Down Beer

Have you ever wondered if beer from a ballpark or summer concert venue is the same as the beer at a restaurant or bar? Recently, Chemir was asked to test the alcohol content of brews from various local stadiums. Everyone’s heard the myths about beers being “watered down,” but we got to the bottom of the issue in the same way we answer analytical chemistry questions everyday.

Background

During fermentation, yeast is used to metabolize the sugars in wort (unfermented beer) to alcohol and carbon dioxide. This is when the wort becomes beer. The quantity of fermentable sugars in the wort and the variety of yeast used in fermentation are the primary factors that determine the amount of alcohol in the final beer product. Additional fermentable sugars are sometimes added to increase alcohol content, and enzymes are often added for certain styles of beer (primarily "light" beers) to convert more complex carbohydrates to fermentable sugars. Additionally, low temperatures and too little fermentation time decrease the effectiveness of yeasts, and consequently decrease the alcohol content.

Here in St. Louis, Missouri, beer (and a lot of it) is prepared at 5% alcohol content. The true acceptable range for ethanol content has been established to be ± 0.3 % of the advertised ethanol content which is usually 5.0 % by volume for most beer and 4.2 % by volume for light beer.

Samples

We obtained samples of cans, bottles and draught beers from several different local sporting and concert venues. Ten different samples, including both regular and light beer, were tested. The samples were all filtered prior to analysis and then diluted in water

Analysis

Following preparation, the samples were tested by GC-FID using isopropyl alcohol as an internal standard. GC-FID is a separation technique used for the analysis of volatile components, such as ethanol. Upon injection of the sample, the components enter the GC column that is often an open tubular capillary column with an inner coating of a stationary phase. Components within the column migrate by use of a carrier gas, such as helium, and appropriate thermal conditions while separation occurs by exploiting a difference in the volatility and polarity of the components. The resulting chromatograms can be used to confirm the identity of a component through retention time, and the intensity is in proportion to the concentration.

Results

Through the course of the analysis, it was found that all of the beers contained ethanol within their accepted levels (± 0.3 % of 5.0 % by volume for regular beer and 4.2% by volume for light beer). See Chart 1 below for actual alcohol levels of each sample.

So if you live in the St. Louis area, you can be assured that when you enjoy your brew this summer while watching your favorite team or listening to your favorite band, you are consistently getting your money’s worth.

Chart 1

Beer location	Regular or Light	Average Ethanol Content (v/v%)
Indoor concert venue (bottles)	Light	4.16%
Football stadium (cans)	Light	4.36%
Baseball stadium (cans)	Light	4.15%
Baseball stadium (draught)	Light	4.18%
Indoor concert venue (draught)	Light	4.18%
Outdoor concert venue (draught)	Light	4.33%
Civic center (cans)	Regular	4.76 %
Civic center (draught)	Regular	4.88 %
Football stadium (draught)	Regular	4.97 %
Outdoor concert venue (draught)	Regular	4.87 %

Beer Trivia:

The beer-drinkingest day in America isn't Super Bowl Sunday but...the Fourth of July.
Beer recipes have been found on Babylonian clay tablets from over 6000 years ago.
Beer is the best-selling adult beverage in the world. In America, it continues to outsell its rivals wine and liquor 7 to 1.
A beer lover or enthusiast is called a cerevisaphile.